1. Field of the Invention
The present invention relates to a light fixture comprising at least one light source, which light source is eclectically connected to an ignition circuit, which ignition circuit is further connected to a power unit, which power unit comprises an electronic ballast, which lamp is supervised by at least one thermo switch, which thermo switch by increasing temperature protects the light source by disconnecting the power supply to the light source.
The present invention further relates to a method for temperature supervision of a light fixture, in which light fixture a beam of light is generated by at least one light source, in which light fixture a number of blowing units generates airflow for cooling the light fixture, in which light fixture thermo sensors detect the temperature.
2. Description of Related Art
U.S. Pat. No. 5,978,196 concerns a thermal protection system for use with a lighting fixture includes a temperature-sensitive switch responsive to the ambient temperature which may have a rating less than that of the lamp. The temperature-sensitive switch controls the operation of a suitably higher rated control device connected to the lamp to turn the lamp off when the ambient temperature above the thermal switch exceeds a predetermined level.
U.S. Pat. No. 4,713,721 describes a two-terminal A.C. device is described which can be series connected with a lighting fixture to prevent overheating of the fixture in an overload condition, namely, when a lighting element exceeding the power rating of the fixture is installed. In broad terms, the device includes a bidirectional, self-extinguishing switch which can be triggered to conduct current between the two terminals of the device, and control circuitry operable from the voltage difference and current between the two terminals occurring in use to regulate the triggering of the switch. The control circuitry includes triggering circuitry which generates triggering signals from the voltage difference across the terminals of the device and normally applies the triggering signals to the control terminal to permit a predetermined measure of conduction. In an overload condition detection circuitry detects an overload current and activates trigger signal suppressing circuitry which temporarily suppresses the application of triggering signals to the switch thereby reducing the mean level of the current delivered to the fixture in an overload condition. In an overload condition, the lighting fixture is operated in a dim or intermittent fashion thereby indicating the overload condition to the user.